What is a schema?
A schema (plural schemata) is a hypothetical mental structure for representing generic concepts stored in memory. It's a sort of framework, or plan, or script. According to Stein and Trabasso (1982), schemata are thought to have these features:
Schemata are composed of generic or abstract knowledge; used to guide encoding, organization, and retrieval of information.
Schemata reflect prototypical properties of experiences encountered by an individual, integrated over many instances.
A schema may be formed and used without the individual's conscious awareness.
Although schemata are assumed to reflect an individual's experience, they are also assumed to be shared across individuals [in a culture?].
Once formed, schemata are thought to be relatively stable over time.
We know more about how schemata are used than we do about how they are acquired.
Driscoll suggests that a schema is analogous to:
A play, in that it has a basic script, but each time it's performed, the details will differ.
A theory, in that it enables us to make predictions from incomplete information, by filling in the missing details with "default values." (Of course, this can be a problem when it causes us to remember things we never actually saw...)
A computer program, in that it enables us to actively evaluate and parse incoming information.